How to take a full advantage of the Advertising?

I set a few advertising campaign, but always confused about the data.
There are high impressions but only about 1% clicks, and the spent is a high cost, with low sales, what should I do about that? To lower the price or optimize the keywords?
I tried to add the keywords with the most clicks or impressions to the search terms, but seems not work well.
And I have no idea how much should I set on the bid, it’s too costy.
Anyone who knows about that, any suggestion?

Look at each keyword. If it’s costing you money but not getting sales then drop it.
You should have visible on the keyword page an idea about suggested price for page 1. Perhaps set some at that level.
You can if you want set your bid maximum high but will cost you.

Try different keywords, what is common across multiple items may be high price compared to words more specific to particular items. Including multiple word keywords.

An ideal to aim for is the spend on the ads to be under 10 percent of the orders generated. 5 percent is of course better but start aiming for a point and fiddle about over time.

Lots of views but few clicks suggests the ad is not appearing in areas of the right interest. Are some keywords you are winning too broad? For instance if I wanted a black candle for a goth friend then a half dozen adverts for ‘candle’ would be likely irrelevant as odds are the candles would be not black.